Fundamental aspects of the local approach to cutaneous ulcers

Papain Covalent Immobilization in Bacterial Cellulose Films as a Wound Dressing

Ideally, the dressings used in the clinic have characteristics that help the wound closure process. Among several factors that affect the success of this healing process, there is debridement. It manages the wound bed components and the re-epithelialization process. Still, the property of debridement is not generally associated with dressings. Here, we show a chemically modified bacterial cellulose film conjugated to a proteolytic enzyme, papain, as a dressing with debridement properties. Bacterial cellulose films were reacted with a spacer derived from succinic acid and finally had this enzyme covalently immobilized in its structure by an amide bond. FT-IR and UV-vis showed bands typically of bioconjugated polymer. Enzymatic immobilization was very effective under the conditions applied with high yield (33% w/w), and these remained activated after the coupling reaction. The bacterial cellulose film with the enzyme papain attached to it was also very compatible with fibroblast cells, suggesting that it could be a promising wound dressing material for future research.

Collagen-Based Nanofibers for Skin Regeneration and Wound Dressing Applications

Skin regeneration after an injury is very vital, but this process can be impeded by several factors. Regenerative medicine is a developing biomedical field with the potential to decrease the need for an organ transplant. Wound management is challenging, particularly for chronic injuries, despite the availability of various types of wound dressing scaffolds in the market. Some of the wound dressings that are in clinical practice have various drawbacks such as poor antibacterial and antioxidant efficacy, poor mechanical properties, inability to absorb excess wound exudates, require frequent change of dressing and fails to offer a suitable moist environment to accelerate the wound healing process. Collagen is a biopolymer and a major constituent of the extracellular matrix (ECM), making it an interesting polymer for the development of wound dressings. Collagen-based nanofibers have demonstrated interesting properties that are advantageous both in the arena of skin regeneration and wound dressings, such as low antigenicity, good biocompatibility, hemostatic properties, capability to promote cellular proliferation and adhesion, and non-toxicity. Hence, this review will discuss the outcomes of collagen-based nanofibers reported from the series of preclinical trials of skin regeneration and wound healing.

Safety of Silk-elastin Sponges in Patients with Chronic Skin Ulcers: A Phase I/II, Single-center, Open-label, Single-arm Clinical Trial

Background:

Although traditional wound dressings such as collagen scaffolds promote granulation tissue formation, the efficacy of these dressings in chronic wounds is limited because of high susceptibility to bacterial growth. Biomaterials that can be applied to chronic wounds should have an anti-bacterial function. We previously reported that administering a silk-elastin solution that forms moisturizing hydrogels to wound surfaces of diabetic mice reduced bacterial growth and promoted granulation tissue formation compared with control or carboxymethyl cellulose hydrogels. We hypothesized that silk-elastin promotes wound healing in human chronic wounds by suppressing bacterial growth.

Methods:

An open-label, clinical case series was conducted with a prospective, single-arm design at Kyoto University Hospital in Kyoto, Japan. In this study, 6 patients with chronic skin ulcers of any origin (2 < ulcer area (cm²) < 25) on their lower extremities were included; patients with critical ischemia were excluded. Silk-elastin sponges were applied and covered with a polyurethane film without changing the dressing for 14 days. Inflammation triggered treatment discontinuation due to fear of infection. The primary study endpoint was adverse events, including inflammation and infection.

Results:

Poor hydrogel formation, possibly due to continuous exudation, was observed. No serious adverse events were noted. Two patients discontinued treatment on day 6 and day 7, respectively, due to inflammation, but they were not infected. The other 4 patients completed the 14-day silk-elastin sponge treatment without infection.

Conclusion:

Silk-elastin sponge is safe for chronic skin ulcers, and its ability to promote wound healing should be determined by confirmatory clinical trials.

Consensus on the diagnosis and management of chronic leg ulcers - Brazilian Society of Dermatology

BACKGROUND

Chronic leg ulcers affect a large portion of the adult population and cause a significant social and economic impact, related to outpatient and hospital care, absence from work, social security expenses, and reduced quality of life. The correct diagnosis and therapeutic approach are essential for a favorable evolution.

OBJECTIVE

To gather the experience of Brazilian dermatologists, reviewing the specialized literature to prepare recommendations for the diagnosis and treatment of the main types of chronic leg ulcers.

METHODS

Seven specialists from six university centers with experience in chronic leg ulcers were appointed by the Brazilian Society of Dermatology to reach a consensus on the diagnosis and therapeutic management of these ulcers. Based on the adapted DELPHI methodology, relevant elements were considered in the diagnosis and treatment of chronic leg ulcers of the most common causes; then, the recent literature was analyzed using the best scientific evidence.

RESULTS

The following themes were defined as relevant for this consensus - the most prevalent differential etiological diagnoses of chronic leg ulcers (venous, arterial, neuropathic, and hypertensive ulcers), as well as the management of each one. It also included the topic of general principles for local management, common to chronic ulcers, regardless of the etiology.

CONCLUSION

This consensus addressed the main etiologies of chronic leg ulcers and their management based on scientific evidence to assist dermatologists and other health professionals and benefit the greatest number of patients with this condition.

Skin Wound Healing Process and New Emerging Technologies for Skin Wound Care and Regeneration

Skin wound healing shows an extraordinary cellular function mechanism, unique in nature and involving the interaction of several cells, growth factors and cytokines. Physiological wound healing restores tissue integrity, but in many cases the process is limited to wound repair. Ongoing studies aim to obtain more effective wound therapies with the intention of reducing inpatient costs, providing long-term relief and effective scar healing. The main goal of this comprehensive review is to focus on the progress in wound medication and how it has evolved over the years. The main complications related to the healing process and the clinical management of chronic wounds are described in the review. Moreover, advanced treatment strategies for skin regeneration and experimental techniques for cellular engineering and skin tissue engineering are addressed. Emerging skin regeneration techniques involving scaffolds activated with growth factors, bioactive molecules and genetically modified cells are exploited to overcome wound healing technology limitations and to implement personalized therapy design.